U.S. patent application number 11/418305 was filed with the patent office on 2006-12-28 for methods of preparing organic-inorganic hybrid binder compositions and nonwoven products.
This patent application is currently assigned to Dynea Austria GmbH. Invention is credited to Elena Pisanova, Robert Schmidt, Alexander Tseitlin.
Application Number | 20060293440 11/418305 |
Document ID | / |
Family ID | 37396230 |
Filed Date | 2006-12-28 |
United States Patent
Application |
20060293440 |
Kind Code |
A1 |
Tseitlin; Alexander ; et
al. |
December 28, 2006 |
Methods of preparing organic-inorganic hybrid binder compositions
and nonwoven products
Abstract
Methods of producing curable water-soluble organic-inorganic
hybrid binder compositions that are based on the use of polyols
containing a plurality of pendant hydroxyl groups and
organooxysilanes. The curable water-soluble organic-inorganic
hybrid binders prepared are useful in producing nonwoven products
such as glass fiber products, polyester fiber products and mineral
wool products.
Inventors: |
Tseitlin; Alexander;
(Mississauga, CA) ; Schmidt; Robert; (Thornhill,
CA) ; Pisanova; Elena; (Mississauga, CA) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Dynea Austria GmbH
Krems
AT
|
Family ID: |
37396230 |
Appl. No.: |
11/418305 |
Filed: |
May 5, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60678213 |
May 6, 2005 |
|
|
|
Current U.S.
Class: |
524/557 |
Current CPC
Class: |
C08G 77/06 20130101;
C08L 2666/04 20130101; C08L 29/04 20130101; C08L 29/04 20130101;
C08F 16/06 20130101; C08G 83/001 20130101; C08J 5/24 20130101; C08K
5/5415 20130101; C08F 8/42 20130101; C08L 83/04 20130101; C08K
5/5406 20130101; C08J 2329/04 20130101; C08K 5/5415 20130101; C08L
83/04 20130101; C08F 8/42 20130101; C08G 77/442 20130101; D04H 1/64
20130101; C08J 5/043 20130101; D04H 1/587 20130101; C08K 5/5406
20130101 |
Class at
Publication: |
524/557 |
International
Class: |
C08L 29/04 20060101
C08L029/04 |
Claims
1. A curable organic-inorganic aqueous binder composition prepared
by a process comprising combining the following components: (A) a
polyol, (B) an organooxysilane, and a catalytic amount of (C) an
acid or a base.
2. The curable organic-inorganic aqueous binder composition
according to claim 1, wherein the polyol is at least one linear,
branched or cyclic organic compound having at least two alcohol
groups.
3. The curable organic-inorganic aqueous binder composition
according to claim 1, wherein the polyol is at least one of a low
molecular weight polyalcohol, a polyvinyl alcohol, a
polysaccharide, and a carbohydrate.
4. The curable organic-inorganic aqueous binder composition
according to claim 1, wherein the polyol is a polyvinyl alcohol
formed from a partially hydrolyzed polyvinyl acetate, or a
copolymer of ethenol and vinyl acetate, and wherein the polyvinyl
alcohol has been hydrolyzed from 70 mole % to 97 mole %
5. The curable organic-inorganic aqueous binder composition
according to claim 1, wherein the organooxysilane is at least one
compound of the following general formula:
R.sup.1.sub.nSi(OR.sup.2).sub.4-n wherein R.sup.1 and R.sup.2 are
each optionally substituted with at least one halogen and are
independently selected from a C.sub.1 to C.sub.5 alkyl and aryl;
and n is 0-3, wherein the majority of monomers has n =0 or 1 and
the majority of R.sup.1 and R.sup.2 are C.sub.1 to C.sub.5
alkyl.
6. The curable organic-inorganic aqueous binder composition
according to claim 5, wherein R.sup.1 and R.sup.2 are independently
selected from a C.sub.1 to C.sub.5 alkyl and n=0-1.
7. The curable organic-inorganic aqueous binder composition
according to claim 1, wherein the process further comprises a step
of neutralizing the composition to have a pH of 4-9 after component
(A) has reacted with component (B).
8. The curable organic-inorganic aqueous binder composition
according to claim 7, wherein component (C) is an acid and wherein
the neutralizing step is performed with a nitrogenous base.
9. The curable organic-inorganic aqueous binder composition
according to claim 7, in a concentrated form having a 30-50 wt %
solids based on the total weight of the curable aqueous
composition.
10. The curable organic-inorganic aqueous binder composition
according to claim 7, in a diluted form having a 2-12 wt % solids
based on the total weight of the curable aqueous composition.
11. A nonwoven product, prepared by a process comprising the steps
of: applying to a nonwoven substrate, the curable organic-inorganic
aqueous binder composition of claim 10 to form a product and
heating the product to effect cure.
12. The nonwoven product of claim 11, wherein the nonwoven
substrate is glass fiber, polyester fiber or mineral wool.
13. The nonwoven product according to claim 11, wherein the
nonwoven product is a fiberglass insulation material, a fiberglass
mat or a fiberglass filter material.
14. The nonwoven product according to claim 11, wherein the
nonwoven product is polyester fiber filtration material.
15. A method of forming a curable organic-inorganic aqueous binder
composition comprising combining the following components: (A) a
polyol, (B) an organooxysilane, and a catalytic amount of (C) an
acid or a base.
16. The method according to claim 15, wherein the polyol is at
least one of a low molecular weight polyalcohol, a polyvinyl
alcohol, a polysaccharide, and a carbohydrate.
17. The method according to claim 15, wherein the organooxysilane
is at least one compound of the following general formula:
R.sup.1.sub.nSi(OR.sup.2).sub.4-n wherein R.sup.1 and R.sup.2 are
each optionally substituted with at least one halogen and are
independently selected from a C.sub.1 to C.sub.5 alkyl and aryl;
and n is 0-3, wherein a majority of the monomers has n=0 or 1 and a
majority of the R.sup.1 and R.sup.2 are C.sub.1 to C.sub.5
alkyl.
18. A method of forming a nonwoven product comprising the steps of:
forming a curable organic-inorganic aqueous binder composition by
combining the following components: (A) a polyol, (B) an
organooxysilane, and a catalytic amount of (C) an acid or a base,
neutralizing the pH of the curable aqueous composition, and
applying to a nonwoven substrate, the neutralized curable aqueous
composition to form a product, and heating the product to effect
cure.
19. The method according to claim 18, wherein the neutralization
step is performed with a nitrogenous base.
20. The method according to claim 18, wherein the nonwoven
substrate is glass fiber, polyester fiber or mineral wool.
Description
[0001] This Nonprovisional application claims priority under 35
U.S.C. .sctn.119(e) on U.S. Provisional Application No(s).
60/678,213 filed on May 6, 2005, the entire contents of which are
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to organic-inorganic hybrid
binder compositions that are thermosetting resin compositions,
methods for producing water-soluble organic-inorganic hybrid
binders that are based on the use of organic polymers containing a
plurality of pendant hydroxyl groups and organooxysilanes, and
which organic-inorganic hybrid binders are useful for the
manufacture of nonwoven products including glass fiber, polyester
fiber and mineral wool products, such as insulation materials,
glass fiber mats, filters and the like.
BACKGROUND OF THE INVENTION
[0003] Phenol-formaldehyde binders have been the primary binders in
the manufacture of fiberglass and mineral wool insulation. These
binders are low-cost and easy to apply and readily cured. They
provide a strong bond, and yet maintain elasticity and a good
thickness recovery to obtain a full insulating value. However,
there is a strong desire in the market for a binder based on
chemistry other than HCHO. Though, there are a number of
formaldehyde-free compositions that have been developed, there
still exists a need for alternative fiberglass binder systems that
provide the performance advantages of phenol-formaldehyde resins in
a formaldehyde-free system.
[0004] Alternative chemistries have been developed to provide
formaldehyde-free binder systems. Alkoxides or halosilanes are used
for modification of organic polymers containing pendant hydroxyl
groups in EP 0 581 576 to form films exhibiting high levels of
physical properties such as tensile, hardness and tensile strength,
and one of them is an organic-inorganic composition. A disadvantage
of the disclosed process is that the reaction is conducted under
substantially anhydrous conditions in organic solvent.
[0005] Silanes in conjunction with colloidal organic particles are
disclosed in DE 196 47 369 A1 in the form of a nano composites for
binding glass fibers, mineral fibers or wood materials. Silicon
compounds in US 2004/0092189 A1 are also used as binders for the
composites for building and automobile industry. In U.S. Pat. No.
5,780,530 there are disclosed thermosetting coating compositions
containing a polyol resin, a curing agent reactive with the polyol,
a hydrolyzate/polycondensate of tri- or tetraethoxysilane, and a
catalyst. Silane in this application is used as a coupling
agent.
[0006] Polyfunctional organic-inorganic compositions comprising
linear and cyclic hydrosiloxanes in U.S. Pat. No. 6,844,394 are
used as coating materials. The method disclosed utilizes a
hydrosilylation reaction, which must be carried out at elevated
temperatures in organic solvent, followed with removing the solvent
by distillation.
[0007] ES 2174680 discloses low-density hybrid organic-inorganic
compositions that are used for making a monolithic heat insulation
materials.
[0008] Ethoxysilanes are described as additives to polycarboxy
polymer binding resins in US 2005/021421 enhancing aging
performance, particularly under hot, humid conditions.
[0009] The systems described in the above disclosures, have serious
disadvantages as insulation binders, such as limited water
dilutabilty, limited storage life, or emission potential adding to
the volatile organic compounds (VOC) or other emissions during
processing of the binder.
SUMMARY OF THE INVENTION
[0010] The present invention relates methods for producing
organic-inorganic hybrid binder compositions, comprising combining
component (A) at least one polyol comprising at least one pendant
hydroxyl groups, component (B) at least one organooxysilane, and a
catalytic amount of component (C) an acid or a base. In addition,
the present invention relates to the organic-inorganic hybrid
binder compositions produced by the present methods. Also, the
present invention relates to nonwoven products, such as glass fiber
products, polyester fiber products and mineral wool products, such
as insulation products, glass fiber mat products, filter products
and the like prepared with the present organic-inorganic hybrid
binder compositions.
[0011] The inventive methods for producing the organic-inorganic
hybrid binders are characterized by their use of polyols and
organooxysilanes to produce a water-soluble resin composition that
comprises sol-gel products of the co-condensation of a water
solution of the polyol with the silane containing a plurality of
alkoxysilyl groups and optionally silanol groups, wherein the
resultant compositions utilize a condensation reaction of silanol
groups, which are formed in-situ, resulting from hydrolysis of the
silane organooxy groups with each other and with hydroxyl groups
possessed by the polyol.
[0012] The thermosetting resin compositions of the present
invention are based on a system comprising a silicate component and
an organic resin component chemically bonded through interaction of
hydroxyl groups of the polyol and the silanol groups of the
silicate component.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The following detailed description and examples are given in
an effort to those desiring to practice the present invention, and
as such should not be deemed to unduly limit the present invention
or the equivalents encompassed thereby as set forth in the claims
appended hereto, and the equivalents encompassed thereby. In this
respect, those of ordinary skill in the art will realize that
various minor changes may be made in the materials, procedures and
methods set forth herein, without departing from the spirit or
scope of the present invention.
[0014] Organic-Inorganic Hybrid Binder Compositions--Production
Methods
[0015] The present invention is based on the Inventors' discovery
of stable water-soluble thermosetting organic-inorganic hybrid
binders for nonwovens that are obtained by hydrolysis of at least
one organooxysilane followed by co-condensation of the resulting
silanol(s) with at least one polyol in the presence of alkaline or
acidic catalysts, to thereby form the stable water-soluble
thermosetting organic-inorganic hybrid binders for nonwovens.
[0016] Thus, the present invention provides a method for producing
a water-soluble thermosetting organic-inorganic hybrid binder that
is useful in the manufacture of nonwoven products (e.g., glass
fiber, polyester fiber and mineral wool products) on the basis of
organic polymers containing plurality of pendant hydroxyl groups
and organooxysilane.
[0017] In one embodiment, the inventive method provides for the
production of an aqueous thermosetting organic-inorganic hybrid
binder composition, comprising an aqueous mixture of a
water-dilutable or dispersible adduct of a co-condensation reaction
of at least one monomeric organooxysilane component and at least
one polyol comprising at least two pendant hydroxyl groups, wherein
the water-dilutable or dispersible adduct of the co-condensation
reaction is a polyolsilane copolymer, and wherein the
co-condensation reaction takes place in the presence of a catalytic
amount of an inorganic or organic acid or a catalytic amount of an
alkali.
[0018] The polyol can be linear, branched or cyclic and may be any
of a wide variety of materials, including but not limited to at
least one of a low molecular weight polyalcohol, a polyvinyl
alcohol, a polysaccharide, and a carbohydrate. Preferably, the
polyol is at least one of polyethylene glycol (to make
2,3-dihydroxydioxane), diethylene glycol, dialkylene glycol (to
make an oligomeric condensation product) such as 1,2-propylene
glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene
glycol, 1,4-butylene glycol, polyethylene glycols having the
formula HO(CH.sub.2CH.sub.2O).sub.nH where n is 1 to about 50, and
the like, and their mixtures. Other suitable polyols (i.e.
containing at least three hydroxy groups) can be used, such as
glycerin, (to make 2,3-dihydroxy-5-hydroxymethyl dioxane) as well
as unalkylated or partially alkylated polymeric glyoxal derived
glycols such as poly (N-1',2'-dihydroxyethyl-ethylene urea),
dextrans, glyceryl monostearate, ascorbic acid, erythrobic acid,
sorbic acid, ascorbyl palmitate, calcium ascorbate, calcium
sorbate, potassium sorbate, sodium ascorbate, sodium sorbate,
monoglycerides of edible fats or oils or edible fat-forming acids,
inositol, sodium tartrate, sodium potassium tartrate, glycerol
monocaprate, sorbose monoglyceride citrate, polyvinyl alcohol,
.alpha.-D-methylglucoside, sorbitol, dextrose, and their
mixtures.
[0019] It is most preferred to use polyvinyl alcohol (PVOH) as the
polyol. The preferred number average molecular weight (Mn) for the
polymers containing plurality of pendant hydroxyl groups is at
least 5,000. It is more preferred that the Mn is 7,000 to 85,000.
It is most preferred that the Mn is 10,000 to 25,000. The PVOH can
be a partially hydrolyzed polyvinyl acetate, or a copolymer of
ethenol and vinyl acetate. Fully hydrolyzed grades of PVOH, i.e.,
at least 98 mole % hydrolyzed, provide high tensile strength of the
final product. However, these fully hydrolyzed grades are
characterized by a higher viscosity of aqueous solutions.
Preferably, the PVOH is from 70 mole % to 97 mole % hydrolyzed.
More preferably, the PVOH is from 80 mole % to 90 mole %
hydrolyzed.
[0020] The monomeric organooxysilane is at least one compound of
the following general formula:
R.sup.1.sub.nSi(OR.sup.2).sub.4-n
[0021] wherein R.sup.1 and R.sup.2 are each optionally substituted
with at least one halogen and are independently selected from a
C.sub.1 to C.sub.5 alkyl (such as methyl, ethyl, propyl or butyl)
and aryl (such as phenyl, tolyl and the like); and n is 0-3,
[0022] wherein the majority of monomers has n=0 or 1 and the
majority of R.sup.1 and R.sup.2 are C.sub.1 to C.sub.5 alkyl.
Preferably, less than 2 mole % of all of the organooxysilane
monomers have R.sup.1 or R.sup.2 as an aryl group. More preferably
R.sup.1 and R.sup.2 are independently selected from a C.sub.1 to
C.sub.5 alkyl and n =0-1. Most preferably, the monomeric
organooxysilane is tetraethoxysilane (TEOS, a.k.a.
tetraethylorthosilicate) and/or methyl(triethoxy)silane (MTEOS,
a.k.a. methyl-triethylorthosilicate).
[0023] The mixture of polyol and monomeric organooxysilane produces
a water-soluble resin composition that comprises sol-gel products
of the co-condensation of a water solution of the organic polymer
containing the plurality of pendant hydroxyl groups with the silane
containing plurality of alkoxysilyl groups and optionally silanol
groups, wherein the resultant compositions utilize a condensation
reaction of silanol groups, which are formed in-situ, resulting
from hydrolysis of silane alkoxy groups with each other and with
hydroxyl groups possessed by the organic polymer. In other words,
the cured composition contains at least two interpenetrating
polymers--a crosslinked polymer (e.g. PVOH) containing alcohol
groups (wherein at least some of the alcohol groups have reacted
with siloxane or polysiloxane groups) and polysiloxane.
[0024] The condensation reaction takes place in the presence of a
catalytic amount of an organic acid and/or inorganic acid or a
catalytic amount of an alkali. Preferably, the amount of acid or
alkali is about 1.25 wt % or less based on the total amount of
polyol and organooxysilane. More preferably, the amount is about
0.85 wt % or less. The mixture undergoing the condensation reaction
does not necessarily have to be heated, but is preferably heated to
less then 100.degree. C. to speed the reaction. More preferably,
the mixture is heated to 50-75.degree. C. Typically, completion of
the reaction is signified by the solution becoming clear.
[0025] The reaction between the polyol component (A) and the
monomeric organooxysilane component (B) is a two-stage process
wherein both stages are performed in situ. At the first stage, the
monomeric organooxysilane is hydrolyzed to a silanol, and then it
condenses into polysiloxane and partially reacts with the hydroxyls
of the polyol. It is preferred to use an acidic catalyst for
component (C) because the reaction of the hydroxyls of the polyol
performs better in an acidic media, so curing is performed at low
pH. In the case of using an alkaline catalyst for component (C),
the pH is shifted to acidic for curing prior to application on the
substrate and curing itself takes longer at the same
temperature.
[0026] In the inventive method, the acid is not specifically
limited in amount (other than being present in a catalytic amount)
or in type, although it is preferably selected from the group
consisting of hydrochloric acid, sulfuric acid, phosphoric acid,
formic acid, acetic acid, citric acid, propionic oxalic acid,
p-toluenesulfonic acid, benzoic acid, phthalic acid and maleic
acid.
[0027] Likewise, the base is not specifically limited in amount
(other than being present in a catalytic amount) or in type,
although it is preferably selected from the group consisting of
sodium hydroxide, potassium hydroxide, calcium hydroxide, tin
compounds (dibutyltin dilaurate, dibutyltin dioctoate and
dibutyltin diacetate) and the like.
[0028] In order to reduce the corrosivity of the aqueous
thermosetting organic-inorganic hybrid binder composition, it is
preferred that the aqueous composition comprising components (A),
(B) and (C) is neutralized to a pH of 4-9 after completion of the
reaction between the polyol and the monomeric organooxysilane.
Preferably, the pH is neutralized to 6-8 after completion of
reaction. Depending upon the final pH of the reaction mixture, any
effective acid or base can be used for neutralization. In the event
that the reaction is catalyzed with acid, the neutralization can be
carried out with a basic salt (such as an alkaline hydroxide in a
concentration of less than 2N, preferably less than IN) or a
nitrogenous base such as an ethanolamine (e.g. diethanolamine). The
use of a nitrogenous base is especially preferred because it gives
less ash content, does not dilute the product (alkalis have to be
used in concentrations not higher than 1N), and overall the final
product has better mechanical properties.
[0029] Organic-Inorganic Hybrid Binder Compositions--Methods of
Use
[0030] The water-soluble thermosetting organic-inorganic hybrid
binder compositions of the instant invention are advantageously
used as binders with glass fiber products, polyester fiber products
and mineral wool products, including fiber glass materials,
insulation materials, and the like. Advantages of the water-soluble
thermosetting organic-inorganic binders are that no hazardous
emissions are produced thereby during manufacture, or after
production, and at the same time they allow for improved mechanical
properties in products produced therewith. It is noted that
stability of the binder composition can be improved by neutralizing
to a pH of 4-9 (preferably about 6-8) after completion of
reaction.
[0031] The curable (thermosetting) water-soluble organic-inorganic
hybrid binder compositions are generally aqueous compositions that
are applied to a nonwoven material or substrate by conventional
techniques such as, for example, spraying, padding, saturating,
roll coating, beater deposition, or the like, followed by
subsequent curing of the compositions to form a non-woven product.
Preferably, the aqueous composition is prepared and stored in a
concentrated form having 30-50 wt % solids, wherein the wt % is
based on the weight of the entire aqueous composition. The
viscosity of the concentrated form of the aqueous composition is
preferably 750-4,500 centipoise as measured at 20.degree. C.
Immediately prior to application, it is preferred that the aqueous
composition is diluted to have 2-12 wt % solids. The viscosity of
the diluted form of the aqueous composition is preferably 5-7
centipoise as measured at 20.degree. C.
[0032] It was found that the aqueous composition is stable for at
least two weeks at room temperature and at least two months when
refrigerated (at .about.4.degree. C.).
[0033] More particularly, the aqueous water-soluble
organic-inorganic hybrid binder composition, after it is applied to
a nonwoven material or substrate is heated to result in drying and
curing of the aqueous thermosetting resin composition. The duration
and temperature of heating affect the rate of curing and properties
development of the treated substrate. Heat treatment (curing) of
the aqueous (waterborne) thermosetting resin binder composition can
take place at temperatures from Room Temperature (about 23.degree.
C.) up to about 150.degree. C., for a time period of from a few
minutes (e.g., 5 - 10 minutes) up to an hour, or a few hours, or
more (e.g., 1-12 hours), depending on the specific materials and
temperatures utilized. Heat treatment at about 100.degree. C. to
about 150.degree. C. for a time period of 5 to 10 minutes is
considered preferable and recommended. Curing at temperatures of
higher than 150.degree. C. can result in rapid water evaporation
and lead to a considerably dry composition, but which is not a
substantially cured composition.
[0034] In an embodiment of the invention, the curable aqueous
organic-inorganic hybrid binder composition includes other
components, e.g. emulsifiers, plasticizers, anti-foaming agents,
biocide additives, anti-mycotics including, e.g., fungicides and
mold inhibitors, adhesion promoting agents, colorants, waxes,
antioxidants, corrosion inhibitors and combinations thereof. It is
envisioned that a polycarboxy polymer (such as a homopolymer or
copolymer prepared from unsaturated carboxylic acids including but
not limited to acrylic acid, methacrylic acid, crotonic acid,
maleic acid and the like) can be added to the mixture of components
(A) and (B) and in small amounts such as a ratio of the number of
equivalents of carboxy, anhydride, or salts thereof of the polyacid
to the number of equivalents of hydroxyl in the polyol being
0.001/1 to 0.94/1. It is most preferred that the curable aqueous
composition does not contain essentially any polycarboxy
polymer.
[0035] In an embodiment of the invention, the curable aqueous
composition includes solvents other than water to promote intimate
mixing of the components.
[0036] The following examples are provided as an aid to those
desiring to practice the instant invention as disclosed herein, and
are not to be construed as being limiting thereto.
EXAMPLE 1
[0037] 500 g of 25% by weight aqueous polyvinyl alcohol (Celvol
205) and 10 g of 1N hydrochloric acid were charged into a kettle
incorporating a stirrer and heating means, and mixed at room
temperature. 110 g of tetraethoxysilane added to the mix with
stirring, and the mix is heated to 60-65 degrees C. for about 6
hours until the solution clears (signifying that the reaction has
essentially completed) the reaction mixture is then neutralized
with diethanolamine to pH=6-8.
EXAMPLE 2
[0038] 500 g of 30% by weight aqueous polyvinyl alcohol (Celvol
502) and 10 g of citric acid were charged into a kettle
incorporating a stirrer and heating means, and mixed at room
temperature. 250 g of tetraethoxysilane added to the mix with
stirring, and the mix is heated to 60-65 degrees C. for about 2
hours until the solution clears (signifying that the reaction has
essentially completed).
EXAMPLE 3
[0039] 500 g of 25% by weight aqueous polyvinyl alcohol (Celvol
205) and 10 g of 1N sodium hydroxide were charged into a kettle
incorporating a stirrer and heating means, and mixed at room
temperature. 110 g of tetraethoxysilane added to the mix with
stirring, and the mix is heated to 60-65 degrees C. for about 3
hours until the solution clears (signifying that the reaction has
essentially completed) the reaction mixture is then neutralized
with 1N HCl to pH=6-8.
EXAMPLE 4
[0040] 150 g of 30% by weight aqueous polyvinyl alcohol (Celvol
502), 15 g of glycerol and 3 g of citric acid were charged into a
kettle incorporating a stirrer and heating means, and mixed at room
temperature. 80 g of tetraethoxysilane added to the mix with
stirring, and the mix is heated to 60-65 degrees C. for about 2
hours until the solution clears (signifying that the reaction has
essentially completed).
EXAMPLE 5
Treatment of Nonwovens and Tensile Testing of Treated Nonwovens
[0041] The binder of Example 1 was applied to a glass fiber
specimen (WHATMAN 934-AH) by saturation method and the excess
binder was recovered by vacuum, and the specimen was then cured in
the oven at 180.degree. C. for 10 minutes. The binder add-on was
28% (dry binder weight based on the weight of glass).
[0042] The cured sheet was then cut into 1 inch by 4 inch strips
tested individually for dry tensile strength by Lloyd Instruments
LRX PLUS tensile tester at a crosshead speed of 2 inches/minute.
Wet tensile strength was measured on strips soaked in 85.degree. C.
water for 10 minutes with a Lloyd Instruments LRX PLUS tensile
tester at a crosshead speed of 2 inches/minute. The test results
are presented in Table 1 along with those of two comparatives (A
and B). TABLE-US-00001 TABLE 1 Tensile Testing of Treated Nonwovens
Dry Tensile Wet Tensile Sample (kgf) (kgf) Retention (%) Example 1
5.71 5.64 98.7 Comparative A.sup.1 5.52 4.68 84.9 Comparative
B.sup.2 5.48 4.7 85.8 .sup.1"Comparative A" contains a phenol
formaldehyde binder. .sup.2"Comparative B" contains a
polyacid-polyol binder from U.S. Pat. No. 5,661,213.
The tensile testing results reported in Table 1 show that the
Inventive Example 1 provides an advantageous dry tensile and wet
tensile strength, and also show an advantageous amount of
retention.
* * * * *